Exam 1

  1. Metainformation

    Tag Value
    fileProbability_uva-independent-events-406-en_uva-independent-events-406-en
    nameuva-independent-events-406-en
    sectionProbability/Elementary Probability/General Rules/Independent events
    typeschoice
    solutionFALSE, TRUE, FALSE, FALSE
    TypeConceptual
    LanguageEnglish
    LevelStatistical Literacy
    IRT-Difficulty3.001
    p-value0.3027

    Question

    50 Patients are randomly nursed on one of two types of mattresses, and after three days they are assessed for signs of pressure ulcers. (bedsores):

    ————— ——————- ————————- frequency some pressure ulcers (D) no pressure ulcers (not D) mattress type I 8 12 mattress type II 10 20 ————— ——————- ————————-

    We want to know whether pressure ulcer formation is (in)dependent on the mattress type used. mattress type. Indicate which of the following reasoning is correct.


    1. FALSE: Dependent, because P(D ∩ I) ≠ 0
    2. TRUE: Dependent, because P(D | I) ≠ P(D)
    3. FALSE: Independent, because P(D | I) = P(I)
    4. FALSE: Independent, because P(D ∪ I) = P(D) + P(I) - P(D ∩ I)

    1. Dependent, because P(D ∩ I) ≠ 0: Incorrect
    2. Dependent, because P(D | I) ≠ P(D): Correct
    3. Independent, because P(D | I) = P(I): Incorrect
    4. Independent, because P(D ∪ I) = P(D) + P(I) - P(D ∩ I): Incorrect